I thought too long about the possibility of Marathon’s humanity expanding beyond Sol Core (Mercury through Mars) on a larger scale than the Obatala Institute, and it became this.

Way back before the Icarus-Thermopylae War, the UESC sent its terraforming machines to the satellites of Jupiter; by 2525, the Jovian Republic had firmly established its independence from Sol Core. Even in later centuries, where the Republic would act as one of the furthest lines of defense against the Pfhor, they weren’t terribly fond of the UESC, and general sentiment was that little of value would be lost if Sol Core fell.

The Jovian population consists mostly of humans, former slaves of the Pfhor, and the odd defector from the Empire; their hull classification symbol is ‘JNV’ (Jovian Navy Vessel).